He Likes To Suck.

[Zenith and Aaron]

This is Zenith, we got him 2 years ago when he was a kitten. About 6 months - 1 year after we got him he started doing this. He only does it on out chests. When he does it on mine and I have him laying along my body he creeps closer and closer to my beard, really giving it a good combing sometimes. After he is done, the blanket is absolutely soaked, he's really sucking. I've read many explanations, but was wondering what you all think.

 

[Letta]

All my cats did that. As long as they are happy and it's not a sign of stress I think it's just an endearing trait of personality.
The most given explanation is that they were separated too early from their mom. But mine were not and they still did it. So who knows. My view on it is that you are their caregiver you take care of them, feed them, play with them ect.. and they feel safe and happy with you which allow them to go back to kittenhood. Their mom protected them, you protect them not so different.. We call ourselves cat "parents" after all.
It can be a sign of stress but you know your cat and if he is happy and still doing it then it is just him being happy

 

[MistyDawn]

First: What a big, beautiful boy! He's stunning and appears to be made very happy by this.

I have one who does this. He's young so he may outgrow it but he only sucks faces. He's my little face hugger. You can try a catsifier, maybe lay on it awhile so it has your scent on it to encourage him to suckle it instead. Maybe even put it on your chest like the blankets (weird, I know, and I imagine you never imagined yourself contemplating putting a pillow with nipples on your chest and letting a cat suck it, but life takes us in funny directions.) Sometimes cats who do this were separated from their mothers at the wrong time or too suddenly. Sometimes, it just feels good and reminds them of having a mom when they were kittens, similarly to why cats knead on soft things. It's a way of them bonding with you as parental figures.

Aside from the Catsifier, I have no real advice, if you want to stop it. I just learn to enjoy having my face licked and kneaded on with some light claw contact. I love him and it's his way of loving me.